1. Field
The present application relates to large rotating turbomachinery, for example, steam and gas turbines and large electrical generators, and more particularly to a coupling hole alignment tool, system and method to align two corresponding coupling holes of two mating flanges on the rotating elements.
2. Description of the Related Art
Couplings, which may include shaft end flanges, must have bolt holes accurately aligned to install precisely fitted bolts. The bolts extend from a bolt hole in one coupling half into a bolt hole in another coupling half and then are secured, securing the coupling halves to one another. For example, a large turbine rotor is aligned to another large turbine rotor or to a generator rotor where each turbine rotor or generator rotor include a plurality of bolt holes to be aligned with corresponding bolt holes in the other turbine rotor or generator rotor. The weight of each rotor to be aligned may be as much as 200 tons. The rotors include a flange type coupling with approximately 12 to 30 bolt holes where each bolt hole may include a diameter between 1.5 inches to 3.5 inches. By design, these bolts, once installed, tightly fit within the bolt hole, for example having approximately 0.001 inch clearance on the diameter.
Most commonly, a hydraulic jack is used to turn one coupling half. A temporary pin sized to fit a coupling bolt hole is loaded in a bolt hole of the coupling half being rotated. The force delivered by the hydraulic jack is then imposed on the pin to effect rotation on the coupling half. Because of the tight clearance of the bolt in the bolt hole, precise alignment of the mating coupling flanges is quite difficult and time consuming using the hydraulic jack. A less difficult and/or less time consuming alignment of two shaft end flanges is desired.